Electrical connector



Dec. 5, 1939. o. J. NELSON ELECTRICAL CONNECTOR Filed April 26, 1935 INVENTO R Oscar J/Vlson ATTORNEY Patented Dec. 5, 1939 UNITED STATES PATENT Oscar J. Nelson, North Canton, Ohio, assignor to The Hoover Company, North Canton, Ohio, a corporation of Ohio Application "April 26, 1935, Serial No. 18,352

4 Claims. (Cl. 173-361) This invention relates to electrical connecting tures of novelty will be apparent from the'followdevices, and more particularly to terminal fiting specification describing two embodiments of tings for the flexible conductor cables in common the invention which are illustrated in the acuse, which fittings are frequently known at atcompanying drawing, in which:

tachment plugs and provide a structure by which Fig. 1 is a view in front elevation of a plug 5 the conductor or conductors of such flexible cable embodying the invention, showing the plug as may be conveniently and quickly attached to, or mechanically attached to its cable;

detached from, the conductor or conductors of a Fig. 2 is a view in side elevation of the struccompanion fitting, such as a wall outlet, to ture shown in Figure 1; establish electrical connection therebetween. Fig. 3 is an enlarged view in transverse section,- 10- The outer portions of such terminal fittings are taken on line 3-8 of Fig. 2;

necessarily formed of insulating material, except Fig. 4 is an enlarged view in longitudinal secfor exposed contacts electrically connected to the tion, taken on line 4-4 of Fig. conductors which are usually in the form of pro- Fig. 5 is a view in front elevation of a modified jecting parallel blades which are adapted to be o m of plugv embodying the invention. the Parts inserted through lots into engagement with conf sa d plu being p rman nt y m lded tog th tacts in the companion fitting. Such terminal Fig. 6 is a view in side elevation of the strucfittings are subject to severe compression and iml s w in u e 5; pact strains when they are not engaged with the 7 is a View in longitudinal s taken outlet fitting, by reason of being dropped upon 011 e of and fioors, by having heavy weights placed upon them, 8 is a View in P pe of certain O he by careless handling of the cable to which they Parts Of the structure shOWn n Figs- 1 t0 are attached which results in impact of the fitting In l. th invention p s s p vid with other obje t and i many th r ways, 11-, the body of an electricalattachment plug with a is therefore highly desirable that such fittings be notch adapted o receive. t e c nductor cable and 25 so constructed as to Withstand both impact and being no larger tha such s t ar compression strains without impairment, and for Opening, threat, of such notch being a owe this purpose th body portion of h fittings is than the diameter of the cable. It will be evifrequently formed of soft rubber, or similar resildent that, With this construction. the Cable y ient and di tortabl ateriaL be forced into the notch, either by spreading the 30 Many electrical devices are provided with a notch eemplessing the e. bot asthe conductor cord having a terminal fitting of this ports e forced together- The p may thus kind, o that ch de i may b temporarily be supported and held out of the way and not connected to an electrical outlet, and when the left to drag o t on the fl or mp i t device is not in use the conductor is frequently other objects, impaet With c might ju e 35 coiled and is supported by, or near, such device. such Object the P bO The cables of It is desirable that, during such periods of disuse electrical devices are frequently coiled p D of an electrical device, the terminal fitting of its jections on such device, for storage when the conductor cable be kept off of the fioor, where it device is not in use, and such case a Pl 40 might be injured, and-be supported so as to minidy the s nt nv n a be enga ed mize the danger of its being subjected to impact with one turn of cable ot o y t hold the with obj ts, plug in a safe position but also to prevent the One of the objects of the present invention is cable fremllnwindingto provide simple a d efiective means for sup.. In the embodiments of the invention-illustrated 5 porting a t rmi fittingor tt t plug in the .drawing herewith, the notch is formed in A further object is to provide means for detachthe body of the P attachment fitt g. In ably mechanically attaching a terminal fitting Figs. 1 to there is s wn a conductor cable II to any portion of its conductor cable. A still containing a twisted P r Of in ulated stranded further object is to provide a terminal fitting conductors and a pair of fi e cords 3. of

with attaching means by which it may be supcotton or other suitable material. twisted with the 50 ported, which means are of simple a d d rabl conductors, the conductors and the cords being construction and entail a minimum of manipulacovered with a suitable insulating and wear-retion to attach the fittin to, or detach it from, its sistin veri s t ru or si lar mat rial,

support. to form a conductor cable which is substantially Still further objects of the invention and fearound in cross section, which is very flexible,.-and 55 which can be distorted slightly by radial compression.

The structure illustrated in Figs. 1 to 4 and Fig. 8 is a plug of the assembled type, the parts 7 thereof being detachably secured together in order to facilitate assembly upon a conductor cable, as well as repair of replacement. In such structure, contact blades H are held rigidly in spaced parallel relation by a disc |5 of insulating material, the blades |4 passing through holes IS in the disc I5 and having their rear portions bent against the rear surface of the disc and secured in place by rivets l8 which pass through the disc and such portions H. In order to connect the conductors l2 electrically to the respective contact blades H, the portions I! are threaded to receive screws l 9, by which the bared ends of the conductors may be held thereto. Screws 20 are also passed through the disc |5 from the front and are threaded into anchor members 2| embedded in a cover 22 of molded insulating material, to hold the disc l5 and its contacts assembled in such cover. A strain relief member 23, which may be formed of rubber or any other suitable material is located within the cover 22 to the rear of the disc l5, and is provided with openings 24 therethrough to receive the conductors l2, the cords l3 being passed around the member 23, and knotted as shown in Fig. 3. It will be understood that such structure prevents any tendency toward impairment of the electrical connection of the conductors to the contact blades by endwise strains on the cable, since such strains are transmitted directly to the cover 22, through the strain relief member.

As shown the cover 22 is roughly frustro-conical in shape, widened at the front end to receive the disc l5, which is clamped against an annularinner seat 25 in the cover by the screws 20. At its rear end the cover 22 is formed with an opening 26 which receives the conductor cable and communicates with the enlarged recess in which the disc l5, strain relief member 23 and other parts are housed. The rear portion of the cover 22 is preferably flared outwardly away from the cablereceiving opening 26 to form an annular rounded surface 21 in order to prevent sharp bending of the conductor cable.

The cover member 22 may be conveniently formed of any suitable molded insulating material such as vulcanized rubber or other rigid compound of that nature, but is preferably formed of molded soft rubber or similar yieldable mate- .rial in order to preclude injury by impact with other objects. In accordance with the present invention, the cover 22 is provided with a laterally extending projection 28, preferably integral with the cover, having a notch 29 therein so as to form outwardly extending fingers 30 which are so spaced circumferentially that the conductor cable can beforced between them and will be frictionally held in the notch. The ends of the fingers 30 are preferably curved slightly toward each other, so that the notch 29 is circular in shape for about 270 degrees to form a. throat 3| narrower than the diameter, and then flaring outwardly, as shown at 32, to facilitate entry of the cable into the notch. It will be understood that, if the cover 22 and the projection 28 are formed of rigid material, the Width of the throat 3| must be such that the cable II can be compressed sufliciently to enter it. If the projection 28 is formed of soft rubber, or similar material, the throat 3| can be wider because the fingers 30 can be bent apart to facilitate entry of the cable, and the resilience of both i the cable and the fingers 30 can be relied upon to hold the parts engaged.

In Figs. 5 to '7 the invention is illustrated in a plug of soft rubber molded permanently upon the conductor cable. Such plug is formed by removing the insulation of a conductor cable 33 at its end to bare the insulated conductors 34, the insulation being also removed from the ends of such conductors so that they may bereversely bent, as shown at 35, in Fig. 7, and electrically connected to contact blades 36 by rivets 31, or in any desired manner. In constructing such a structure, the parts are held in their proper relationship and the plug body 38 of soft rubber is molded about them. The molded plug body 38 is provided, as shown in Figs. 5 to 'l, with two diametrically positioned notches 39 spaced circumferentially between the contact blades 36. Such notches 38, as in the modification shown in Figs. 1 to 4, are substantially circular for about 270 degrees, with a throat 40 between fingers 4|, the end faces of which flare outwardly as shown at 42. It will be apparent that only a single notch could be provided, if desired. .The rear portion of the plug body as shown is of rectangularshape in crosssection, the wide flattened surfaces 42 curving outwardly to meet the edge of the front face of the plug which is preferably circular except for the intersection by the notches. In the construction shownthe provision of two notches facilitates attachment of the plug to, or detachment from,

the bight of the conductor cable, since one notch can be widened through distortion of the plug body by squeezing together circumferentially the fingers at the sides of the other notch.

It will be apparent that, in either modification, the plug can be readily attached to any convenient part of the conductor cable, and that the clamping effect of the fingers 30, or 4 will be sufficient to hold the plug from sliding lengthwise of the cable and to hold the plug from accidental displacement from the cable. The structure is simple and inexpensive to manufacture, and affords a readily usable and effective means of holdin the plug in such a way as to prevent uncoiling of the cable and minimize the danger of impact of the plug with other objects.

What is claimed is:

1. A terminal contact fitting for an insulated cable containing an electric conductor, comprising a contact member electrically connected to the conductor, a body of insulating material connected to and supporting said contact member, and a pair of outwardly extending fingers carried by said body spaced throughout their length by a distance no greater than the diameter of the cable and adapted for detachable clamping engagement with said cable.

2. A terminal contact fitting for an insulated cable containing an electric conductor, comprising a contact member electrically connected to the conductor, a cover of insulating material enclosing the connection between the conductor and said contact member, said cover being formed of soft rubber and having an integral portion thereof formed with an open notch of such width as to grip said cable frictionally to secure said fitting detachably to said cable.

3. A terminal contact fitting for an insulated cable containing an electric conductor, comprising a contactmember electrically connected to the conductor, a body of resilient insulating material surrounding the conductor and supporting said contact member, said body having portions integral therewith and spaced to form an open marginal notch in which the cable may be yield-' said body having inherently resilient fingers ably and clampingly engaged. thereon spaced to form a notch adapted through- 4. A terminal contact fitting for an insulated out its depth to receive said cable with the walls cable containing an electric conductor, comprlsof said notch in clamping engagement with said ing a contact member electrically connected to cable.- I the conductor and a body of insulating material OSCAR J. NELSON. connected to and supporting said contact member, 

